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PREEMPT_SCHEDULE_NOT(9) Driver Basics PREEMPT_SCHEDULE_NOT(9)

NAME

preempt_schedule_notrace - preempt_schedule called by tracing

SYNOPSIS

__visible void __sched notrace preempt_schedule_notrace(void);

ARGUMENTS

void
no arguments

DESCRIPTION

The tracing infrastructure uses preempt_enable_notrace to prevent recursion and tracing preempt enabling caused by the tracing infrastructure itself. But as tracing can happen in areas coming from userspace or just about to enter userspace, a preempt enable can occur before user_exit is called. This will cause the scheduler to be called when the system is still in usermode.
To prevent this, the preempt_enable_notrace will use this function instead of preempt_schedule to exit user context if needed before calling the scheduler.

COPYRIGHT

January 2017 Kernel Hackers Manual 4.8.